A functional study of plasma-membrane calcium-pump isoform 2 mutants causing digenic deafness

Ca2+ enters the stereocilia of hair cells through mechanoelectrical transduction channels opened by the deflection of the hair bundle and is exported back to endolymph by an unusual splicing isoform (w/a) of plasma-membrane calcium-pump isoform 2 (PMCA2). Ablation or missense mutations of the pump cause deafness, as described for the G283S mutation in the deafwaddler (dfw) mouse. A deafness-inducing missense mutation of PMCA2 (G293S) has been identified in a human family. The family also was screened for mutations in cadherin 23, which accentuated hearing loss in a previously described human family with a PMCA2 mutation. A T1999S substitution was detected in the cadherin 23 gene of the healthy father and affected son but not in that of the unaffected mother, who presented instead the PMCA2 mutation. The w/a isoform was overexpressed in CHO cells. At variance with the other PMCA2 isoforms, it became activated only marginally when exposed to a Ca2+ pulse. The G293S and G283S mutations delayed the dissipation of Ca2+ transients induced in CHO cells by InsP3. In organotypic cultures, Ca2+ imaging of vestibular hair cells showed that the dissipation of stereociliary Ca2+ transients induced by Ca2+ uncaging was compromised in the dfw and PMCA2 knockout mice, as was the sensitivity of the mechanoelectrical transduction channels to hair bundle displacement in cochlear hair cells.

Binding Hot Spots in the TEM1–BLIP Interface in Light of its Modular Architecture

Proteins bind one another in aqua's solution to form tight and specific complexes. Previously we have shown that this is achieved through the modular architecture of the interaction network formed by the interface residues, where tight cooperative interactions are found within modules but not between them. Here we extend this study to cover the entire interface of TEM1 beta-lactamase and its protein inhibitor BLIP using an improved method for deriving interaction maps based on REDUCE to add hydrogen atoms and then by evaluating the interactions using modifications of the programs PROBE, NCI and PARE. An extensive mutagenesis study of the interface residues indeed showed that each module is energetically independent on other modules, and that cooperativity is found only within a module. By solving the X-ray structure of two interface mutations affecting two different modules, we demonstrated that protein-protein binding occur via the structural reorganization of the binding modules, either by a "lock and key" or an induced fit mechanism. To explain the cooperativity within a module, we performed multiple-mutant cycle analysis of cluster 2 resulting in a high-resolution energy map of this module. Mutant studies are usually done in reference to alanine, which can be regarded as a deletion of a side-chain. However, from a biological perspective, there is a major interest to understand non-Ala substitutions, as they are most common. Using X-ray crystallography and multiple-mutant cycle analysis we demonstrated the added complexity in understanding non-Ala mutations. Here, a double mutation replacing the wild-type Glu,Tyr to Tyr,Asn on TEM1 (res id 104,105) caused a major backbone structural rearrangement of BLIP, changing the composition of two modules but not of other modules within the interface. This shows the robustness of the modular approach, yet demonstrates the complexity of in silico protein design.

Optical quality of the nasendoscope with and without the endosheath

With the increasing use of the endosheath in clinical practice, we set out to investigate the quality of the nasendoscope image produced with and without an endosheath. It has been suggested by some users that the endosheath degrades the image. We used a spectrophotometer to assess the optical transmission of the endosheath and found no selective chromatic absorption. However, on requesting nine experienced users to document whether they could differentiate between the sheathed and unsheathed endoscope, a significantly correct answering pattern was obtained in repeated blinded experiments. This suggests that individuals can distinguish between the sheathed and unsheathed nasendoscope view and that the image is indeed altered when an endosheath is employed.

Rapid diagnosis of Penicillium marneffei infection by fine needle aspiration cytology

This report describes the use of fine needle aspiration (FNA) cytology to make a rapid diagnosis of Penicillium marneffei infection in an HIV positive patient. P marneffei is a thermally dimorphic fungus that is a mould at 25 degrees C and a yeast at 37 degrees C. It multiplies by fission. It can be easily mistaken for various other infections that are characterised by the presence of histiocytes with phagocytosed yeast cells. In smears the demonstration of yeast cells with a distinctive central septum confirms the diagnosis.

Phase I trial of bortezomib in combination with topotecan in advanced solid tumor malignancies

12004

Background: Bortezomib (B) and topotecan (T) have been shown in pre-clinical testing to be synergistic. Based on this data we have performed a phase I study to determine the maximally tolerated dose and toxicities (tox) of B and T delivered sequentially. Methods: 24 pts (KPS<ECOG 3) with advanced malignancies were treated with T (2.0, 2.5, 3.0 or 3.5 mg/m2 in sequential cohorts) IV on days 1 and 8 of each three week cycle. B 1.3 mg/m2 iv was administered six hours following T on days 1 and 8, and alone on days 4 and 12. Pts were treated in cohorts of 3, the MTD dose was expanded to include 10 additional pts for PK analysis. There was no limit on prior therapies. DLT was defined as any gr 3 or 4 non-hematologic toxicity not reversible in 48h or any gr 3 thrombocytopenia lasting >7 days or associated with bleeding or any gr 4. Results: Tumor types included: breast (4), ovary (5), lung (3), others (12). 24 pts were entered (11M 13F). The median age was 55 (range: 34–83). DLT was thrombocytopenia, observed in two pts at 3.5 mg/m2 and one pt at 3.0 mg/m2 (MTD). Other grade 3 or 4 tox included fatigue, lymphopenia, hypomagnesemia, and hypertriglyceridemia. Of the 24 enrolled pts, stable disease was observed in 4 (4 or 5 cycles), 9 progressed, 5 were inevaluable and 6 are too early. PK analysis is pending. Conclusions: T and B delivered sequentially are well tolerated on a weekly schedule. DLT is thrombocytopenia. PK will be presented.(Supported by NCI Grant CA33572).

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Phase II study of hydroxyurea and gemcitabine in recurrent or persistent squamous cell cancer of the head and neck

15524

Background: Preclinical studies demonstrate increased activity when hydroxyurea (HU) is given prior to gemcitabine (G). Clinical feasibility was demonstrated in a phase I trial (Yen, et. al. Cancer Chemother Pharmacol. 2002 ). We performed a phase II trial treating patients (pts) with squamous cell head and neck cancers (SCCHN). Methods: Pts had metastatic or incurable locally recurrent SCCHN. Prior chemotherapy was allowed, but not required. Serum creatinine ≤2.0 mg/dl, bilirubin <3.0 gm/dl, AST/ALT <5× ULN and KPS ≥60% were required. HU 500 mg orally every 6 hours for 4 doses was given on day 1 of a 21-day cycle. On day 2, 6 hours after HU, G 750 mg/m2 was given over 30 minutes. This sequence was repeated on day 8 and 9. After 8 pts, G was given at 500 mg/m2. G-CSF was given on day 10 and until the WBC count was >10k/μl. The primary endpoint was response rate (RR), with an early stopping rule for <3 objective responders among the first 18 pts. Results: 22 pts (17 M) were accrued, 16 with prior chemotherapy and 19 with prior radiation. The first 8 pts received G 750 mg/m2. Two pts died of neutropenic fever (NF) during course 1. Subsequently 14 pts received G 500 mg/m2. 18 pts were evaluable for response, with 1 still in follow-up. Partial response was seen in 1 pt, stable disease in 9, and progressive disease in 8. The overall median survival of the 22 pts was 6 months and the median progression free survival (PFS) was 2 months. The primary toxicity was hematologic. Grade 4 neutropenia was seen in 7/22 pts during the 1st cycle (5 at G 750 mg/m2) with 5 cases of NF. Grade 4 thrombocytopenia occurred in 1 pt at G 750 mg/m2. Conclusions: The RR and PFS of treated pts treated were not promising and further accrual is not planned. Analysis of biopsy materials is planned to see if responsive pts can be selected. (Supported by NCI Grant CA33572).

No significant financial relationships to disclose.

Circulating levels of MCP-1 and IL-8 are elevated in human obese subjects and associated with obesity-related parameters

BACKGROUND

Chemotactic cytokines, referred to as chemokines, play an important role in leukocyte trafficking. The circulating levels of chemokines have been shown to increase in inflammatory processes including obesity-related pathologies (e.g. atherosclerosis and diabetes). However, little is currently known about the relationship between chemokines and human obesity. In the present study, we investigated the circulating levels of selected chemokines (monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-1alpha (MIP-1alpha), leukotactin-1, interleukin-8 (IL-8)) and the association between the chemokine levels and obesity-related parameters: body mass index (BMI), waist circumference, fasting glucose and insulin levels, lipids profile, and the level of C-reactive protein (CRP).

METHODS

A total of 100 subjects, 50 obese (BMI>or=25 kg/m2) and 50 who were not obese (BMI<25 kg/m2) participated in the present study. The levels of chemokines and CRP were measured in a fasting state serum by sandwich enzyme-linked immunosorbent assay. Total cholesterol, high-density lipoprotein (HDL)-cholesterol, triglyceride, glucose, and insulin levels were measured by enzymatic analysis and immunoassay.

RESULTS

The circulating levels of MCP-1 and IL-8 in the serum were significantly (P<0.05) higher in obese subjects (BMI>30 kg/m2) compared with those of nonobese controls (BMI<25 kg/m2). The levels of CRP were positively correlated with BMI (P<0.001) or waist circumference (P<0.0001). The levels of MCP-1 and IL-8 were positively related to BMI (MCP-1, P<0.02; IL-8, P<0.01) and/or waist circumference (MCP-1, P<0.009; IL-8, P<0.03). The levels of MCP-1 were positively related to the levels of CRP (P<0.007) or interleukin-6 (IL-6) (P<0.0001), and negatively related to the levels of HDL-cholesterol (P<0.01). Homeostasis model assessment (HOMA) score was positively related to the levels of MCP-1 (P<0.02) or IL-8 (P<0.03) in obese subject.

DISCUSSION

Our data demonstrated that the circulating levels of MCP-1 and IL-8 are related to obesity-related parameters such as BMI, waist circumference, CRP, IL-6, HOMA and HDL-cholesterol. These findings suggest that the circulating MCP-1 and/or IL-8 may be a potential candidate linking obesity with obesity-related metabolic complications such as atherosclerosis and diabetes.

Up-regulation of metallothionein isoforms in keloid keratinocytes

Keloids are proliferative growths of dermal collagen, usually resulting from excessive tissue response during wound healing. There is evidence that keratinocytes may promote keloidogenesis via epithelial-mesenchymal interactions. Metallothioneins (MTs) are known to be involved in the fundamental cellular processes of growth and apoptosis. In this study, we evaluated the expression of MT isoforms in normal and keloid keratinocytes. The expression patterns of ten functional MT isoforms were assessed using real-time RT-PCR in primary cultures of normal and keloid keratinocytes. The MT-2A isoform was the most abundant MT isoform in both normal and keloid keratinocytes while the MT-1B isoform was absent. There was a significant increase in the mRNA expression of four MT isoforms, viz. MT-1A, 1E, 1F and 2A in keloid keratinocytes as compared to normal keratinocytes. Up-regulation of MT-1A, 1E, 1F and 2A isoforms may play a part in the development of keloids by paracrine signaling.

Protein markers for Alzheimer disease in the frontal cortex and cerebellum

OBJECTIVE

To compare proteins related to Alzheimer disease (AD) in the frontal cortex and cerebellum of subjects with early-onset AD (EOAD) with or without presenilin 1 (PS1) mutations with sporadic late-onset AD (LOAD) and nondemented control subjects.

METHODS

Immunohistochemistry, immunoblot analysis, and ELISA were used to detect and assess protein levels in brain.

RESULTS

In EOAD and to a lesser extent in LOAD, there was increased amyloid beta (Abeta) deposition (by immunohistochemistry), increased soluble Abeta (by immunoblot analysis), and specific increases in Abeta40 and Abeta42 (by ELISA) in the frontal cortex and, in some cases, in the cerebellum. Surprisingly, immunoblot analysis revealed reduced levels of PS1 in many of the subjects with EOAD with or without PS1 mutations. In those PS1 mutation-bearing subjects with the highest Abeta, PS1 was barely, if at all, detectable. This decrease in PS1 was specific and not attributable solely to neuronal loss because amyloid precursor protein (APP) and the PS1-interacting protein beta-catenin levels were unchanged.

CONCLUSIONS

This study shows that in the frontal cortex and cerebellum from Alzheimer disease patients harboring certain presenilin 1 mutations, high levels of amyloid beta are associated with low levels of presenilin 1. The study provides the premise for further investigation of mechanisms underlying the downregulation of presenilin 1, which may have considerable pathogenic and therapeutic relevance.

Sexually inappropriate behaviour in demented elderly people

AIM

To determine the prevalence, aetiology, and treatment profile of abnormal sexual behaviour in subjects with dementia in psychogeriatric practices.

METHODS

A retrospective cross sectional study was conducted in a long term care psychiatry consultation service, community based geriatric psychiatry service, and an inpatient dementia behavioural unit in Edmonton, Canada.

RESULTS

Forty one subjects (1.8%) had sexually inappropriate behaviour. Of those cognitively impaired subjects with sexually inappropriate behaviour, 20 (48.8%) were living in nursing homes and the rest, 21 (51.2%) in the community. Of these subjects, 53.7% had vascular dementia, 22% had Alzheimer's, and 9.8% had mild cognitive impairment. History of alcohol misuse and psychosis were reported in 14.6% and 9.8% of subjects respectively. Twenty seven (65.7%) had verbally inappropriate behaviour and 36 (87.8%) had physically inappropriate behaviour. In this study, verbally inappropriate behaviour was more commonly seen in the community sample (81%) than in the nursing home sample (50%) (p = 0.04). Behavioural treatment was also more commonly seen in the community sample (81%) than in the nursing home sample (45%) (p = 0.01).

CONCLUSION

In this study sexually inappropriate behaviour was seen in all stages of dementia, more commonly associated with subjects of vascular aetiology, and is as commonly seen in community dwelling subjects with dementia as in nursing home subjects.

Surgery and adjuvant radiotherapy vs concurrent chemoradiotherapy in stage III/IV nonmetastatic squamous cell head and neck cancer: a randomised comparison

We compared concurrent combination chemotherapy and radiotherapy with surgery and adjuvant radiotherapy in patients with stage III/IV nonmetastatic squamous cell head and neck cancer. Patients with non-nasopharyngeal and nonsalivary resectable squamous cell head and neck cancer were randomised to receive either surgery followed by adjuvant radiotherapy (60 Gy over 30 fractions) or concurrent combination chemotherapy and radiotherapy (66 Gy in 33 fractions). Combination chemotherapy comprised two cycles of i.v. cisplatin 20 mg m^{− 2} day^{− 1} and i.v. 5-fluorouracil 1000 mg m^{− 2} day^{− 1}, both to run over 96 h given on days 1 and 28 of the radiotherapy. A total of 119 patients were randomised. At a median follow-up of 6 years, there was no significant difference in the 3-year disease-free survival rate between the surgery and concurrent chemoradiotherapy (50 vs 40% respectively). The overall organ preservation rate or avoidance of surgery to primary site was 45%. Those with laryngeal/hypopharyngeal disease subsite had a higher organ-preservation rate than the rest (68 vs 30%). Combination chemotherapy and concurrent irradiation with salvage surgery was not superior to conventional surgery and postoperative radiotherapy for resectable advanced squamous cell head and neck cancer. However, this form of treatment schedule with a view to organ-preservation can be attempted especially for those with laryngeal/hypopharyngeal and possibly oropharyngeal disease subsites.